I've got a Hasty Bake 256 Gourmet. It's a great cooker, here it comes, BUT, it is a fuel hog and you pretty much cannot snuff out your charcoal once you're done using it.
I don't have an M1 but I've spent time looking at it online. Seems like a very good cooker. I doubt the charcoal grate has as much travel as the HB grate, but the additional smoker box with diffuser plate system may make up for that.
Were I to buy again I'd give the M1 strong consideration.